Welcome to the Institute of Cell Biology and Physiology

The newly established Institute of Integrative Cell Biology and Physiology (IIZP) integrates the former Institute of Molecular Cell Biology and the Institute of Zoophysiology.

Our new institute embodies the close connection between physiological and cell biological processes that cannot be fully understood in isolation. At the IIZP, our mission is to explore the complex structures and physiological processes in animal cells and whole organisms across a range of time and length scales. Following this approach, our aim is to develop a comprehensive understanding of the molecular, cellular and biophysical principles of developmentally, physiologically and pathologically relevant processes.

The research activities at the IIZP integrate experiments on individual molecules, isolated cells, tissues and living organisms. We are using a wide range of model systems that include cell cultures, amoebae, crustaceans, nematodes, fruit flies as well as mouse models. For our integrative approach, we combine biochemical and genetic technologies with high-resolution, quantitative microscopy approaches.

Please visit our research groups for more information.


News

December 2021
© Di Meo and Püschel

New pathway identified that regulates axonal mitochondria

Neurons are highly polarized cells that display characteristic differences in the organization of their organelles in axons and dendrites. The kinases SadA and SadB (SadA/B, also called Brsk2 and Brsk1) promote the formation of distinct axonal and dendritic extensions during the development of cortical and hippocampal neurons. The work of Danila Di Meo, Priyadarshini Ravindran, Pratibha Dhumale, Tanmay Sadhanasatish and Andreas Püschel shows that the specific dynamics of axonal mitochondria depends on these kinases. They function as regulators of mitochondrial dynamics through the phosphorylation of the microtubule-binding protein Tau. Suppression of SadA/B in cortical neurons disrupts the balance of mitochondrial fission and fusion and induces the elongation of mitochondria. SadA/B-deficient neurons show an accumulation of hyper-fused mitochondria and the activation of the integrated stress response. SadA/B regulate the interaction of Tau with actin filaments that are essential for the Drp1-mediated fission of mitochondria. The elongation of mitochondria after a loss of SadA/B results from an excessive stabilization of actin filaments and reduction of Drp1 recruitment to mitochondria. The normal dynamics of axonal mitochondria could be restored by mild actin destabilization. These results identify a new pathway that regulates mitochondrial dynamics through Tau.

Funding
The work was supported by the Deutsche Forschungsgemeinschaft.

Original publication
Di Meo, D., Ravindran, P., Sadhanasatish, T., Dhumale, P., Püschel, A.W. (2021). The balance of mitochondrial fission and fusion in cortical axons depends on the kinases SadA and SadB. Cell Rep.  37, 110141. doi: 10.1016/j.celrep.2021.110141.

July 2021
© AG Grashoff

Optimized microscopy method enables single molecule detection under native conditions

WWU researchers optimize super-resolution microscopy application for single molecule detection / Study published as cover story in ChemBioChem
The development of super-resolution microscopy, which was awarded the Nobel Prize in 2014, allows the analysis of cell biological processes with a precision of a few nanometers, making it even possible to differentiate between individual molecules within cells. One limitation of virtually all single-molecule resolved super-resolution approaches, however, is that the target molecules have to be genetically modified to allow precise measurements. Researchers at the WWU Münster have now optimized a protein labeling process so that native, unmodified proteins can be visualized and quantified with molecular resolution in their natural environment.

Background and method
High-resolution microscopy is typically based upon a procedure, in which a transient interaction between a fluorescent probe and the target molecule produces an isolated blinking signal that can be used to calculate its precise localization. For this purpose, however, the molecule of interest is usually genetically modified. For example, DNA-PAINT is based on the fact that a DNA binding site is attached to the target protein, to which a complementary fluorescent DNA strand can bind for detection. Other high-resolution microscopy methods use modifications by fluorescent proteins. Since such genetic modifications are undesirable in many applications and sometimes not even possible, new methods for the detection of unmodified, endogenous proteins are needed.
Lisa Fischer, PhD student in Prof. Carsten Grashoff's group, has therefore developed a procedure called Direct Peptide-PAINT, with which a central cell adhesion protein, Talin, can be labeled by a fluorescent interaction peptide. The first application did not only reveal the molecular distribution of this molecule in differentiating stem cells, it also allowed the first visualization of individual Talin proteins in tissue sections. The new method should therefore allow the investigation of adhesion processes under pathophysiological relevant conditions. The researchers expect that the new technique will be useful to obtain important, molecular insights into disorders that are based on dysfunctional cell adhesion.

Funding
The work was funded by the Deutsche Forschungsgemeinschaft (DFG) and the Human Frontier Science Program.

Original publication
Lisa S. Fischer, Thomas Schlichthaerle, Anna Chrostek-Grashoff, and Carsten Grashoff. Peptide-PAINT Enables Investigation of Endogenous Talin with Molecular Scale Resolution in Cells and Tissues. DOI: 10.1002/cbic.202100301

 

February 2021
The image shows localization clouds of individual adhesion proteins in cells. Many proteins remained undetectable when using conventional analytical methods. By using the new analytical method actual molecular parameters can be determined. Scale bar: 100 nm.
© AG Grashoff

New microscopy analysis allows discovery of central adhesion complex

WWU researchers develop a new method for quantitative single-molecule colocalization analysis /Study published in Nature Communications
Cells of organisms are organized in subcellular compartments that consist of many individual molecules. How these single proteins are organized on the molecular level remains unclear, because suitable analytical methods are still missing. Researchers at the University of Münster together with colleagues from the Max Planck Institute of Biochemistry (Munich) have established a new technique that enables quantifying molecular densities and nanoscale organizations of individual proteins inside cells. The first application of this approach reveals a complex of three adhesion proteins that appears to be crucial for the ability of cells to adhere to the surrounding tissue. The research results have just been published in the journal Nature Communications. more

Funding

The research work was funded by the German Research Foundation (DFG).

Original publication

L.S. Fischer, C. Klingner, T. Schlichthaerle, M.T. Strauss, R. Böttcher, R. Fässler, R. Jungmann, C. Grashoff. Quantitative single-protein imaging reveals molecular complex formation of integrin, talin, and kindlin during cell adhesion. Nature Communications 12, 919 (2021). DOI: 10.1038/s41467-021-21142-2

December 2021
© AG Grashoff

New mechanism of force transduction in muscle cells discovered

WWU researchers reveal mechanobiological function of muscle-specific adhesion protein / Study published in Nature Communications
The ability of cells to sense and respond to their mechanical environment is critical for many cellular processes but the molecular mechanisms underlying cellular mechanosensitivity are still unclear. Researchers at the University of Münster have now discovered how the muscle-specific adhesion molecule metavinculin modulates mechanical force transduction on the molecular level. The research results have just been published in the journal Nature Communications.

Background and methodology
The interaction of cells with their environment is mediated by specialized adhesion structures, which transduce mechanical forces inwards and out of cells. As cellular adhesions consist of hundreds of different proteins, it is still unclear how the mechanical information is transmitted on the molecular level. To study these processes in more detail, the Grashoff laboratory at the WWU Münster develops biosensors that allow the detection of piconewton-scale forces propagated across individual molecules in cells. In their most recent study, the authors applied their microscopy-based technique to the adhesion protein metavinculin, which is expressed in muscle cells and associated with cardiomyopathy, a heart muscle disease.
By analyzing a range of genetically modified cells, the authors demonstrate that the presence of metavinculin changes how mechanical forces are transduced in cell adhesion complexes. “Our data indicate that metavinculin could function as a molecular dampener, helping to resist high peak forces observed in muscle tissues“, explains Prof. Dr. Carsten Grashoff, principal investigator of the study. “This is a very interesting example of how the presence of a single protein can change the way mechanical information is processed in cells.”
Surprisingly, the authors did not observe any indications of cardiomyopathy in mice lacking metavinculin. This suggests that the pathophysiological role of metavinculin is more complex than previously assumed.more

Funding
The research work was funded by the German Research Foundation (DFG).

Original publication
Verena Kanoldt, Carleen Kluger, Christiane Barz, Anna-Lena Schweizer, Deepak Ramanujam, Lukas Windgasse, Stefan Engelhardt, Anna Chrostek-Grashoff, and Carsten Grashoff. Metavinculin modulates force transduction in cell adhesion sites. Nature Communications. DOI : 10.1038/s41467-020-20125-z.

June 2020
© Springer Nature

Myosins: A Superfamily of Molecular Motors

A comprehensive account was published of the current understanding of myosins, actin-based molecular motors, that contains a chapter on the current knowledge of class IX myosins that was contributed by the Bähler group. Class IX myosins demonstrate not only unique motor properties, but simultaneously serve as negative regulators of an important signaling pathway that controls various cellular processes such as e.g. cell morphology and cell migration.